Length Conversion.

One inch equals exactly 2.54 centimeters, a precise international definition adopted in 1959, not a rounded number. To convert inches to centimeters, multiply by 2.54. To go from centimeters to inches, divide by 2.54 (or multiply by 0.3937).

A mile is about 1.609 kilometers, so a kilometer is roughly 0.621 miles. A quick mental shortcut: multiply kilometers by 0.6 for an approximate mile value. A 5K race is 3.107 miles, and a marathon (26.2 miles) is 42.195 kilometers.

Multiply feet by 0.3048 to get meters. For example, 6 feet equals 1.8288 meters. To convert meters to feet, multiply by 3.281. A quick reference: 5 feet is 1.524 m, 10 feet is 3.048 m, and 100 feet is 30.48 m.